DEFINE ALIAS Statement

Purpose

Specifies a name that can be used as a synonym for the set of data type attributes you give to the alias.

Syntax

DEFINE ALIAS [alias-name, attribute,];

Parameters

alias-name

Specifies the name that can be used wherever the explicit data type defined by the specified attributes is allowed.

attributes

The specified attributes that define the alias. Separate each attribute with a comma(,). The attributes that can be specified are any of the attributes for variables that can be returned by a function (for example, those attributes valid in the RETURNS option and attribute). Therefore, you cannot specify an alias for an array or a structured attribute list. However, you can specify an alias for a type that is defined:

in a DEFINE ORDINAL statement
in a DEFINE STRUCTURE statement
in another DEFINE ALIAS statement.

Also, as in the RETURNS option and attribute, any string lengths or area sizes must be restricted expressions.

Missing data attributes are supplied using PL/I defaults.

Description

An alias can be used wherever an explicit data type can be used. Using DEFINE ALIAS, you can define an alias for a collection of data attributes. This lets you assign meaningful names to data types, which can make a program easier to understand. Aliases also let you provide a shorter notation for a set of data attributes, which can decrease typographical errors.

Example

define alias Name   char(31) varying;
define alias Salary fixed dec(7);     /* real by default */
define alias Zip    char(5)           /* nonvarying by default */

Note: Whenever Name is used in a DECLARE statement, it has the attributes char(31) varying.

Restrictions

None.